Added a post-database migration method
Convert address fields in shop configuration
Added basic version of attribute config migration
Sometimes the order of migration steps does matter!
Validate all used columns
Migrate non-advanced product price to subtable
Implemented address migration from serialized collection data
Check ready state before post migration
Added stylect from contao/check
Pass request to renderConfigView
Every migration step will get it's own session attribute bag
Added notification center gateway config

Will now create the gateway table if necessary